1. Field of the Invention
The present invention relates to an apparatus and method for communicating by manual entry on a keypad using a minimum of key stroke entries. More particularly, the invention relates to an apparatus and method for use by the hearing or speech impaired to communicate over the telephone network using a standard twelve key, dual tone, multi-frequency telephone.
2. Description of the Prior Art
For the hearing or speech impaired to effectively communicate over a long distance, several methods have been devised which enable nonverbal communication over a communications network, such as a telephone grid. Such devices include relatively expensive and nonportable radio teletype terminals and communications-adapted computer terminals. Such terminal keyboards typically employ a standard "QWERTY" keyboard which enables the passage of messages by simply typing in the entire message. Such terminals are, of course, deficient in that they are not only expensive, but also are bulky and difficult to transport.
It has been recognized that it is desirable to use a standard 12 key, dual tone multiple frequency (DTMF or Touch-tone) telephone to communicate between the hearing or speech impaired. Utilizing such a standard "Touch-tone" telephone would be inexpensive and provide a partial solution to the problem of transporting bulky communication equipment. A primary difficulty with using such "Touch-tone" telephones is that the industry standard telephone keypad utilizes 12 keys. Ten of the keys represent a single numeric character, while 8 of the keys each represent 3 alphabetic characters.
To utilize such a standard "Touch-tone" telephone for nonverbal communication, past solutions have used multiple keystroke entries to identify a particular alphabetic letter. For example, a first depression identifies which key the desired letter appears on and a second depression identifies which letter of the three possibilities is desired for input.
The necessity for depressing two keys to identify one letter, is of course a major impedimate to effective telecommunication using a standard "Touch-tone" telephone. That is, even short messages require a large number of keystrokes to enter the message.